A REVOLUTIONARY night-vision system developed for the Dutch military makes night-time video images look as clear and colourful as those shot in broad daylight.

The idea was to improve on the fuzzy grey or green pictures that are the hallmark of today's night-vision systems. Although these monochrome images are an improvement on unaided night vision, their lack of colour can make them hard to interpret.

Full-colour night vision would help emergency services and the military better assess their surroundings, says Alex Toet of the TNO research lab in Soesterberg, the Netherlands, who led the team that developed the system. He says it will make it easier to judge distances, enhancing "situational awareness".

Today's night-vision cameras brighten dim images using circuitry that amplifies what little light there is. An alternative technology, which can be used in total darkness, uses infrared sensors to map the heat radiation that emanates from all objects.

But the detectors in night-vision cameras only pick up a limited range of wavelengths, so do not give enough information to generate a colour image, while thermal imaging cameras pick up no colour information at all. In both systems, the image is displayed in various intensities of green or grey, the colours people find easiest to see.

TNO's new system works by sampling the colours in daytime scenes of the same kind as are being viewed, and mapping them onto the night-vision images. The effect is dramatic (see Diagram), making obstacles and terrain much easier to cope with at night.

The research was funded by the Dutch military, whose previous attempts to fake colour effects in night-vision systems were unsuccessful. The results were often "psychedelic" and distracting, according to Sylvester de Bruin of the Dutch ministry of defence.

Toet's technique, revealed in the journal Displays (vol 26, p 15), produces natural-looking colour by sampling colour daytime images in the landscapes in which the system is expected to be used. These might include rural, urban and desert scenes, for example.

The system selects random pixels from the daytime image to obtain a sample of the range of colours in a typical environment. So a pastoral scene would have browns from the trees, greens from the grass, vegetation and tree canopies, and blues for the sky.

In conventional night-vision equipment these colours appear in monochrome shades. The new system maps these shades onto their colour equivalents, assigning say a light grey to the blue of the sky, or a deep, dark grey to the brown of tree trunks. When the system is later used to view a target scene at night, the mapping is reversed, replacing monochrome pixels in the night image with the closest matching colour from the sample image.

Toet envisages that night-vision goggles using the technology will have a range of settings - rural, urban, sea or desert, for example - each with its own mapping. A more advanced system could use GPS positioning data to choose colours based on the specific location where the system is being used.

The system's inventors hope it will improve soldiers' reaction times and reduce the fatigue that develops from scrutinising night images. Preliminary tests on 12 subjects have shown the colour-enhanced images radically improve people's ability to recognise objects.

The technology is being developed into a prototype for night-time helicopter manoeuvres. The initial aim, de Bruin says, is to see whether it improves a pilot's ability to avoid obstacles.

Nah. The way I read it, they've done extensive color mapping and put it on the internal computer chip. So, right out of the box, the scope knows that a particular shade of gray ought to be light brown, for example.

I bet these are expensive right now, but I can wait....

12
posted on 02/10/2005 11:23:19 AM PST
by HeadOn
(When force is the only language understood, you had better speak it.)

Generic mappings like this will, at least on occasion, produce truly weird images.

Especially for the abusers, us folk who used to play 33 rpm records at 45 just to hear the chipmonks. We will use desert settings for forest, and jungle settings for tundra. And, if we are lucky, we will find a bootleg Mars configuration which we can use everywhere, just for fun.

And I'd bet several shades of red once folks knew they were "visible on one of these devices. LOL

As I read your comment, I also thought of the lyrics or title to a song by Procul Harem or some such, i.e., "a whiter shade of pale". I guess after these folks turn red from being seen, they'll turn pale.

Especially for the abusers, us folk who used to play 33 rpm records at 45 just to hear the chipmonks. We will use desert settings for forest, and jungle settings for tundra. And, if we are lucky, we will find a bootleg Mars configuration which we can use everywhere, just for fun.

I'm a technoid so, typically, I hadn't even considered the human factor and it's ability to goof around with almost anything :)

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